Fire doors are frequently provided with mechanical door locks having dead-bolts and spring bolts. These doors are used to prevent a fire spreading in the building. The door is designed to prevent a fire that has started from spreading, regardless of whether the dead-bolt is tripped in the striking plate or not, the door being kept closed by the spring bolt of the door lock having an inclined surface in the closing direction of the door. In the same way, the bolt shall be capable of keeping the door closed in the event of fire, regardless of whether the spring bolt is blocked or not. The fire door can also be provided with an electric striking plate as described in Swedish patent Nos. 9500582-3 or 9700962-5 together with a lock for a mortise sashlock. A problem therefore arises when the door shall also be opened by an automatic door opener, actuated from a button beside the door. The whole concept of an automatic door opener is lost if the door knob must be used in order to open the door.